TW202117050A - Molybdenum thin films by oxidation-reduction - Google Patents

Abstract

A method of forming a molybdenum film by oxidation and reduction is disclosed. A molybdenum oxide film is formed by CVD or ALD using a halide free organometallic molybdenum precursor. The molybdenum oxide film contains low amounts of carbon impurities. The molybdenum oxide film is reduced to form a highly pure molybdenum film. The molybdenum film has low resistance and properties similar to bulk molybdenum.

Description

Redox molybdenum film

The embodiments of the present invention generally relate to a method of forming a high-purity metal film. Certain embodiments provide methods for forming high purity molybdenum films.

Due to its lower electrical resistance and thermal stability compared to other metals, molybdenum thin films have recently attracted a lot of attention. Therefore, molybdenum has become a better material for metal covering, as a conductor instead of cobalt as a covering layer, and/or instead of tungsten as a conductor.

The current molybdenum film deposition process relies on MoF ₆ with mono-silane. This treatment produces a film containing F and Si. In addition, exposure to MoF ₆ precursors can cause damage to the underlying materials on the substrate.

Alternative molybdenum formation processes have relied on organometallic precursors. Films deposited with organometallic precursors usually contain significant amounts of carbon. In both cases, the contaminants of the membrane change the properties of the membrane and make the membrane unsuitable for several applications.

Therefore, there is a need for a method of forming a high-purity molybdenum film and a method of depositing a high-purity film without exposing the substrate to a halide-containing precursor.

One or more embodiments of the present invention relate to a method of forming a molybdenum film. The method includes exposing the surface of the substrate to an organometallic molybdenum precursor and an oxidizing agent to form a molybdenum oxide film. This molybdenum oxide film is reduced to form a molybdenum film.

An additional embodiment of the present invention relates to a method of forming a molybdenum film. This method includes exposing a substrate surface maintained at a temperature in the range of about 100° C. to about 500° C. to a plurality of ALD cycles to form a molybdenum oxide film having a thickness in the range of 0.2 nm to about 100 nm. Each cycle involves exposure to organometallic molybdenum precursors and oxidants. The organometallic molybdenum precursor does not substantially contain halogen atoms. When maintained at a temperature in the range of about 250°C to about 500°C, this molybdenum oxide film is exposed to alcohols to form a molybdenum film.

A further embodiment relates to a method of forming a molybdenum film. This method includes exposing the surface of the substrate to a plurality of ALD cycles to form a molybdenum oxide film having a thickness in the range of 0.2 nm to about 100 nm. Each cycle involves exposure to organometallic molybdenum precursors and oxidants. This molybdenum oxide film has a carbon content of less than or equal to about 5 atomic percent. This molybdenum oxide film is exposed to a reducing agent to form a molybdenum film. This molybdenum film has an impurity content of less than or equal to about 5 atomic percent.

Before describing several exemplary embodiments of the present invention, it will be understood that the present invention is not limited to the details of the architecture or processing steps described in the following specification. The present invention may be other embodiments and may be implemented or executed in various ways.

When used in the scope of this specification and the appended application, the term "substrate" refers to a surface or a part of a surface, on which processing can be performed. Unless clearly indicated otherwise in the context, those skilled in the art will also understand that with regard to a substrate, only a part of the substrate can be referred to. In addition, reference to deposition on a substrate can mean both on a bare substrate and a substrate having one or more films or features deposited or formed thereon.

As used herein, "substrate" refers to any substrate or material surface formed on the substrate, on which film processing is performed during the manufacturing process. For example, the surface of the substrate on which processing can be performed includes materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, Glass, sapphire, and any other materials such as metals, metal nitrides (e.g., titanium nitride, tantalum nitride), metal alloys, and other conductive materials, depending on the application. The substrate includes a semiconductor wafer without limitation. The substrate can be exposed to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam cure and/or bake the surface of the substrate. In addition to the film processing directly on the surface of the substrate itself, in the present invention, any of the film processing steps disclosed can also be performed on the underlying layer formed on the substrate, as explained in more detail later, and the term "substrate surface "Is intended to include this lower layer as the context dictates. Therefore, for example, in the case where the film/layer or part of the film/layer has been deposited on the surface of the substrate, the exposed surface of the newly deposited film/layer becomes the surface of the substrate.

The embodiment of the present invention relates to a method of forming a molybdenum film by oxidation and reduction. Certain embodiments of the present invention advantageously provide methods for depositing metal films with high purity. Certain embodiments of the present invention advantageously provide high purity molybdenum films. Therefore, these high-purity membranes exhibit properties similar to the bulk materials with which they are related. For example, certain embodiments of the present invention provide a molybdenum film having a lower electrical resistance than that of a molybdenum film deposited by a conventional process. Certain embodiments of the present invention advantageously provide molybdenum films that do not use halogen-containing precursors. Certain embodiments of the present invention advantageously provide methods for reducing metal oxides with alcohols.

When used in the scope of this specification and the accompanying patent application, the terms "precursor", "reactant", "reactive gas" and the like are used interchangeably to refer to any gaseous species that can react with the surface of the substrate.

FIG. 1 shows an example processing sequence 100 for the formation of a ruthenium film according to one or more embodiments of the present invention. At step 110, a molybdenum oxide film is formed. According to some embodiments of the present invention, the molybdenum oxide film is formed by exposing the surface of the substrate to the organometallic molybdenum precursor at step 112 and to the oxidizing agent at step 114.

According to Figure 1, the formation of the molybdenum oxide film at step 110 should not be understood as being limited to simultaneous or sequential exposure to the substrate surface. A specific embodiment regarding simultaneous exposure will be described later with reference to FIG. 2. Hereinafter, a specific embodiment of sequential exposure will be described with reference to FIG. 3.

At step 112, the surface of the substrate is exposed to the organometallic molybdenum precursor. The organometallic molybdenum precursor can be any suitable molybdenum precursor used to form a molybdenum oxide film.

In some embodiments, the organometallic molybdenum precursor contains substantially no halogen atoms. Without being limited by theory, it is believed that the use of organometallic molybdenum precursors without halogen atoms prevents damage to the underlying substrate material during the deposition of the molybdenum oxide film.

In certain embodiments, the organometallic molybdenum precursor includes at least one molybdenum-carbon bond. For example, carbonyl ligands are usually linked to the metal center of the organometallic precursor to produce a metal-carbon bond. Without being limited by theory, it is believed that organometallic molybdenum precursors containing molybdenum-carbon bonds exhibit good reactivity, but if used for direct deposition of molybdenum films, they generally provide molybdenum films with significant carbon content.

In certain embodiments, the organometallic molybdenum precursor comprises or consists essentially of one or more of the following: tBuDADMo(CO) ₄ , Cycloheptatriene molybdenum tricarbonyl, bis(tertiary butane) Bis(t-butylimido) bis(dimethylamino) Mo, bis(ethylbenzene)molybdenum, Mo14, CpMo(CO) ₂ (NO) , MeCpMo(CO) ₂ (NO), (Bicyclo[2.2.1]hepta-2,5-diene)tetracarbonyl molybdenum(0)((Bicyclo[2.2.1]hepta-2,5-diene)tetracarbonylmolybdenum( 0)), or molybdenum (CO) ₆ . When used in this way, the organometallic molybdenum precursor "essentially composed of the specified compound", when measured as the molar percentage of the active precursor in the organometallic molybdenum precursor, contains greater than or equal to about 95 %, 98%, 99% or 99.5% of the specified compound.

At step 114, the surface of the substrate is exposed to the oxidant. The oxidant may be any suitable oxidant that reacts with the organometallic molybdenum precursor to form a molybdenum oxide film.

In certain embodiments, the oxidant includes _{one or more of oxygen (O 2} ), ozone, or water. In some embodiments, the oxidant includes plasma of oxygen, ozone, or water. In certain embodiments, the oxidant includes plasma generated _{from oxygen (O 2 ).}

The substrate surface can be maintained at a predetermined temperature during various processing steps. In some embodiments, during the formation of the molybdenum oxide film at step 110, the substrate is maintained at a temperature in the range of about 100°C to about 500°C or about 100°C to about 400°C. In some embodiments, during the reduction of the molybdenum oxide film at step 120, the substrate is maintained at about 250°C to about 500°C, about 250°C to about 450°C, or about 300°C to about 400° The temperature in the range of C.

At step 110, the molybdenum oxide film may be formed to a predetermined thickness. In some embodiments, the molybdenum oxide film has a thickness in the range of about 0.2 nm to about 100 nm, about 0.2 nm to about 10 nm, about 0.2 to about 5 nm, or about 0.5 nm to about 10 nm.

In some embodiments, the molybdenum oxide film has a low carbon content. In some embodiments, the carbon content of the molybdenum oxide film is less than or equal to about 10%, less than or equal to about 5%, less than or equal to about 2%, or less than or equal to about 1% on an atomic percentage basis.

Without being limited by theory, although organometallic molybdenum precursors containing molybdenum-carbon bonds produce molybdenum films with increased carbon impurities, the inventors have found that these precursors produce molybdenum oxide films with relatively low carbon impurities.

Referring again to FIG. 1, at step 120, the molybdenum oxide film is reduced to form a molybdenum film. In some embodiments, reducing the molybdenum oxide film includes exposing the molybdenum oxide film to a reducing agent including alcohols, hydrogen, or hydrogen plasma.

In certain embodiments, alcohols contain 1-4 carbon atoms, 5-8 carbon atoms, or 1-8 carbon atoms. In certain embodiments, the alcohol comprises or consists essentially of one or more of the following: methanol, ethanol, propanol, isopropanol, butanol, or tertiary butanol.

The alcohol can be introduced into the processing chamber by any suitable processing. In some embodiments, alcohols can be introduced by vapor dra. In some embodiments, alcohols can be introduced by direct liquid dispensing.

Without being limited by theory, alcohols that expose the molybdenum oxide film to high temperatures are believed to provide a milder reduction treatment, which minimizes the impact on surrounding substrates compared to harsher reduction reactants such as hydrogen plasma. Material damage.

The processing conditions during the reduction of the molybdenum oxide film can be controlled. In certain embodiments, the pressure of the processing chamber is maintained in the range of about 1 Torr to about 760 Torr, or about 5 Torr to about 350 Torr, or about 10 Torr to about 100 Torr.

The substrate surface can be maintained at a predetermined temperature during various processing steps. In some embodiments, during the formation of the molybdenum oxide film at step 110, the substrate is maintained at a temperature in the range of about 100°C to about 500°C or about 100°C to about 400°C. In some embodiments, during the reduction of the molybdenum oxide film at step 120, the substrate is maintained at about 250°C to about 500°C, about 250°C to about 450°C, or about 300°C to about 400°C. The temperature in the range of C.

The molybdenum film produced by certain embodiments of the present invention is of high purity. In some embodiments, the molybdenum film contains low levels of halogen, nitrogen, carbon, and oxygen. In some embodiments, the molybdenum film has an impurity content of less than or equal to about 10%, less than or equal to about 5%, less than or equal to about 2%, or less than or equal to about 1%. When used here, the "impurity content" is the total atom count of atoms different from molybdenum and hydrogen in the molybdenum film.

In some embodiments, the molybdenum film contains less than or equal to about 5 atomic% carbon, or less than or equal to about 2 atomic% carbon, or less than or equal to about 1 atomic% carbon.

In some embodiments, the molybdenum film contains less than or equal to about 5 atomic% oxygen, or less than or equal to about 2 atomic% oxygen, or less than or equal to about 1 atomic% oxygen.

In certain embodiments, the metal layer contains greater than or equal to about 75 atomic% molybdenum, or greater than or equal to about 80 atomic% molybdenum, or greater than or equal to about 85 atomic% molybdenum, or greater than or equal to about 90 atomic% molybdenum, or Greater than or equal to about 95 atomic% molybdenum.

In some embodiments, the molybdenum film has a bulk resistance similar to that of bulk molybdenum deposited by PVD processing. Molybdenum deposited by PVD processing is understood to be of high purity and low resistance. When used in this way, the "similar" resistance is within +/- 5%, +/- 2%, or +/- 1% of the resistance of the PVD material.

In some embodiments, the molybdenum film has a resistance of less than or equal to about 2000 µohm-cm, or less than or equal to about 1800 µohm-cm, or less than or equal to about 1700 µohm-cm, or less than or equal to about 1600 µohm-cm. , Or less than or equal to about 1500 µohm-cm, or less than or equal to about 1000 µohm-cm, or less than or equal to about 800 µohm-cm, or less than or equal to about 500 µohm-cm, or less than or equal to about 200 µohm-cm , Or less than or equal to about 100 µohm-cm, or less than or equal to about 50 µohm-cm. In some embodiments, the molybdenum film has a resistance of less than or equal to about 20000 ohm ² , or less than or equal to about 10000 ohm ² , or less than or equal to about 5000 ohm ² , or less than or equal to about 2000 ohm ² , or less than or Equal to about 1000 ohm ² , less than or equal to about 500 ohm ² , less than or equal to about 100 ohm ² , or less than or equal to about 50 ohm ² .

Although the general embodiment has been described above with reference to FIG. 1, the following description describes the simultaneous exposure and sequential exposure of the organometallic molybdenum precursor and the oxidant at step 110. Although the processing steps can be different, the reactants are similar to many processing parameters.

Referring to Figure 2, the present invention relates to the deposition of molybdenum oxide film by simultaneous or constant flow treatment. In certain embodiments, the simultaneous or constant flow method is known as the CVD method.

The CVD method described herein simultaneously exposes the surface of the substrate to the organometallic molybdenum precursor and the oxidant. Therefore, in these methods, there is the possibility of a gas phase reaction between the organometallic molybdenum precursor and the oxidant.

In certain embodiments, the organometallic molybdenum precursor and/or oxidant may flow constantly. In certain embodiments, the organometallic molybdenum precursor and/or oxidant may be pulsed.

In some embodiments, the organometallic molybdenum precursor and/or oxidant may be equipped with carrier gas or diluent gas. When used here, the carrier gas or diluent gas can be a non-reactive gas. In certain embodiments, the carrier gas includes argon.

Figure 2 depicts several process diagrams 210, 220, 230, 240 for forming a molybdenum oxide film by CVD process according to one or more embodiments of the present invention. Diagram 210 provides a pulsed flow of organometallic molybdenum precursor and a constant flow of oxidant. Diagram 220 provides a constant flow of organometallic molybdenum precursor and a pulsed flow of oxidant. Diagram 230 provides a constant flow of organometallic molybdenum precursor and a constant flow of oxidant. Diagram 240 provides a pulsed flow of organometallic molybdenum precursor and a pulsed flow of oxidant. Unlike the ALD process described later, in diagram 240, the pulses of the organometallic molybdenum precursor and oxidant overlap during part of the treatment diagram. The flow rate, pressure, and exposure time of the organometallic molybdenum precursor and oxidant can be any suitable value.

The CVD method is continued until the predetermined thickness has been reached. If the predetermined thickness is not reached, the method continues according to the processing diagram until the predetermined thickness is reached. Once the predetermined thickness has been reached, the molybdenum oxide film can be reduced as described above.

As used herein, "atomic layer deposition" or "cyclic deposition" refers to the sequential exposure of two or more reactive compounds to deposit a layer of material on the surface of the substrate. When used in the scope of this specification and the accompanying patent application, the terms "reactive compound", "reactive gas", "reactive species", "precursor", "processing gas" and the like are used interchangeably to mean Substances of species that undergo surface reactions (for example, chemical adsorption, oxidation, reduction) with the surface of the substrate or the materials on the surface of the substrate. The surface of the substrate or a part thereof is respectively exposed to two or more reaction compounds introduced into the reaction zone of the processing chamber.

In the time-domain ALD process, each reactive compound is separately exposed to the substrate with a time delay to allow each compound to adhere and/or react on the surface of the substrate, and then is drained from the processing chamber. These reactive compounds are said to be sequentially exposed to the substrate. In spatial ALD processing, different parts of the substrate surface or materials on the substrate surface are simultaneously exposed to two or more reactive compounds, so that any given point on the substrate is substantially not simultaneously exposed to more than one reactive compound . When used in the scope of this specification and the accompanying patent application, as those skilled in the art will understand, the term "substantially" used in this way means that a small part of the substrate can be exposed at the same time due to diffusion Because of the possibility of multiple reactive gases, simultaneous exposure is not intentional.

In one aspect of the time domain ALD process, the first reaction gas (ie, the first precursor or compound A) is pulsed into the reaction zone, followed by a first time delay. Next, the second precursor or compound B is pulsed into the reaction zone, followed by a second delay. During each time delay, a purge gas such as argon is introduced into the processing chamber to purge the reaction zone or remove any residual reaction compounds or reaction by-products from the reaction zone.

Referring to Figure 3, in some embodiments, as shown in illustration 310, the purge gas flows continuously throughout the deposition process, so that only the purge gas flows during the time delay between pulses of the reactive compound. The reactive compound is pulsed alternately until a desired film or film thickness is formed on the surface of the substrate. In some embodiments, as shown in solution 320, the purge gas may only flow between pulses of reactive compounds. In either scheme, the ALD treatment of pulse compound A, purge gas, compound B and purge gas is a cycle. A cycle can start with compound A or compound B and continue the individual sequence of the cycle until a film with a predetermined thickness is reached.

In an embodiment of the spatial ALD process, the first reaction gas and the second reaction gas (eg, metal precursor gas) are simultaneously delivered to the reaction zone, but separated by an inert gas curtain and/or a vacuum curtain. The substrate moves relative to the gas delivery device so that any given point on the surface of the substrate is exposed to the first reaction gas, the gas curtain, and the second reaction gas.

The cycle of the ALD method is continued until the predetermined thickness has been reached. If the predetermined thickness has not been reached, the method is continued to repeat the deposition cycle until the predetermined thickness is reached. Once the predetermined thickness has been reached, the molybdenum oxide film can be reduced as described above.

Regarding the processing diagrams in Figures 2 and 3, the "pulse" or "dose" used here means the amount of source gas introduced into the processing chamber intermittently or discontinuously. The amount of a specific compound in each pulse can vary with time depending on the duration of the pulse. The specific processing gas may include a single compound or a mixture/combination of two or more compounds, for example, the processing gas described later.

The duration of each pulse/dose can be varied and adjusted to suit, for example, the volumetric capacity of the processing chamber and the ability of the vacuum system coupled to the processing chamber. In addition, the dosage time of the processing gas may vary according to the flow rate of the processing gas, the temperature of the processing gas, the type of control valve, the type of processing chamber used, and the ability of the components of the processing gas to be adsorbed on the surface of the substrate. The dose time can also vary based on the type of layer formed and the geometry of the device formed. The dosage time should be long enough to provide a compound volume sufficient to adsorb/chemically adsorb on substantially the entire surface of the substrate and form a layer of processing gas components on the surface.

Although the above description specifically concerns the formation of the molybdenum film, it is noted that similar processing can also be used for the formation of the tungsten film. In these embodiments, the organometallic molybdenum precursor is replaced by a tungsten precursor. The formed film is a tungsten oxide film, and the tungsten oxide film is reduced to form a high-purity tungsten film. Suitable tungsten precursors include, but are not limited to, cyclopentadienyl tungsten(II) tricarbonyl hydride, bis(tertiary butylimino)bis(dimethylamino)tungsten (VI) )(bis(t-butylimido) bis(dimethylamino) tungsten(VI)), mesitylene tungsten tricarbonyl, tungsten hexacarbonyl, tetracarbonyl(1,5-cyclooctadiene) tungsten (tetracarbonyl( 1,5-cyclooctadiene) tungsten), bis(isopropylcyclopentadienyl) tungsten(IV) dihydride), bis(isopropylcyclopentadienyl) tungsten(IV) dihydride), and bis(cyclopentadienyl) tungsten(IV) dihydride (IV) (bis(cyclopentadienyl) tungsten(IV) dihydride).

Reference throughout this specification to "one embodiment", "certain embodiments", "one or more embodiments", or "an embodiment" means to link this embodiment description Specific features, structures, materials or characteristics of are included in at least one embodiment of the present invention. Therefore, in various places throughout this specification, such as "in one or more embodiments", "in some embodiments", "in one embodiment", or "in one embodiment" The phrase "in an embodiment" does not necessarily refer to the same embodiment of the invention. Furthermore, in one or more embodiments, specific features, structures, materials, or characteristics are combined in any suitable manner.

Although the present invention has been described herein with reference to specific embodiments, those skilled in the art will understand that the embodiments are only examples of the principles and applications of the present invention. Without departing from the spirit and scope of the present invention, it will be obvious to a person skilled in the art that various modifications and changes can be made to the method and equipment of the present invention. Therefore, it is intended that the present invention may include modifications and changes within the scope of the attached patent application and its equivalents.

100: Processing sequence 110, 112, 114, 120: steps 210,220,230,240,310,320: diagram

By referring to the embodiments, some of the embodiments are shown in the accompanying drawings, and a more specific description of the present invention briefly summarized above can be obtained, so that the above-mentioned features of the present invention can be understood in detail. However, it will be noted that the accompanying drawings only illustrate typical embodiments of the present invention, and thus are not considered as limiting the scope of the present invention, as the present invention may recognize other equivalent embodiments.

Figure 1 shows an example processing sequence for the formation of a molybdenum film according to one or more embodiments of the present invention;

Figure 2 shows an exemplary CVD process diagram for the formation of a molybdenum oxide film according to one or more embodiments of the present invention; and

Figure 3 shows an exemplary ALD process diagram for the formation of a molybdenum oxide film according to one or more embodiments of the present invention.

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100: Processing sequence

110, 112, 114, 120: steps

Claims (20)

A method of forming a molybdenum film, the method comprising: Exposing the surface of a substrate to an organometallic molybdenum precursor and an oxidizing agent to form a molybdenum oxide film; and The molybdenum oxide film is reduced to form a molybdenum film. The method according to claim 1, wherein the organometallic molybdenum precursor does not substantially contain halogen atoms. The method of claim 1, wherein the organometallic molybdenum precursor comprises at least one molybdenum-carbon bond. The method according to claim 1, wherein the organometallic molybdenum precursor comprises one or more of the following: tBuDADMo(CO) ₄ , Cycloheptatriene molybdenum tricarbonyl, bis(tertiary butyl imino) ) Bis(t-butylimido) bis(dimethylamino) Mo, bis(ethylbenzene)molybdenum, Mo14, CpMo(CO) ₂ (NO), MeCpMo( CO) ₂ (NO), (Bicyclo[2.2.1]hepta-2,5-diene)tetracarbonylmolybdenum(0)((Bicyclo[2.2.1]hepta-2,5-diene)tetracarbonylmolybdenum(0)) , Or molybdenum (CO) ₆ . The method according to claim 1, wherein the oxidant comprises one or more of the following: oxygen, ozone, water, or a plasma of one or more of the foregoing. The method according to claim 1, wherein the surface of the substrate is maintained at a temperature in a range of about 100°C to about 500°C during the formation of the molybdenum oxide film. The method according to claim 1, wherein the surface of the substrate is simultaneously exposed to the organometallic molybdenum precursor and the oxidant. The method of claim 1, wherein the surface is sequentially exposed to the organometallic molybdenum precursor and the oxidizing agent. The method of claim 8, wherein exposing the substrate to the organometallic molybdenum precursor and the oxidizing agent defines an ALD cycle, and before the molybdenum oxide film is reduced, multiple ALD cycles are performed. The method according to claim 1, wherein the molybdenum oxide film has a thickness in a range of about 0.2 nm to about 100 nm. The method according to claim 1, wherein the molybdenum oxide film has a carbon content of less than or equal to about 5 atomic percent. The method according to claim 1, wherein the surface of the substrate is maintained at a temperature in a range of about 250°C to about 500°C during the formation of the molybdenum film. The method of claim 1, wherein reducing the molybdenum oxide film comprises exposing the molybdenum oxide film to a reducing agent containing an alcohol or hydrogen. The method according to claim 13, wherein the alcohol comprises one or more of methanol, ethanol, propanol, isopropanol, or tertiary butanol. The method according to claim 13, wherein the reducing agent comprises a plasma formed from hydrogen. The method according to claim 1, wherein the molybdenum film has an impurity content less than or equal to about 5 atomic percent. The method of claim 1, wherein the molybdenum film has a bulk resistance similar to that of a molybdenum film deposited by physical vapor deposition. A method of forming a molybdenum film, the method comprising: A substrate surface maintained at a temperature in a range of about 100°C to about 500°C is exposed to a plurality of ALD cycles to form molybdenum monoxide having a thickness in a range of 0.2 nm to about 100 nm The film, each cycle includes exposure to an organometallic molybdenum precursor and an oxidizing agent, the organometallic molybdenum precursor does not substantially contain halogen atoms; and The molybdenum oxide film maintained at a temperature in a range of about 250°C to about 500°C is exposed to an alcohol to form a molybdenum film. The method of claim 18, wherein the molybdenum film has an impurity content less than or equal to about 5 atomic percent. A method of forming a molybdenum film, the method comprising: A substrate surface is exposed to a plurality of ALD cycles to form a molybdenum monoxide film having a thickness in a range of 0.2 nm to about 100 nm. Each cycle includes exposure to an organometallic molybdenum precursor and an oxidizing agent. The molybdenum oxide film has a carbon content of less than or equal to about 5 atomic percent; and The molybdenum oxide film is exposed to a reducing agent to form a molybdenum film having an impurity content less than or equal to about 5 atomic percent.

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